Example Embodiments relate to an image pickup device, and more particularly, to a complementary metal-oxide semiconductor (CMOS) image sensor and a CMOS image sensing system including the same.
An image sensor is a device that converts an optical image into an electrical signal. With recent developments of the computer and communication industries, the demand on CMOS image sensors with improved performance is increasing in various fields such as digital camera, camcorders, personal communication systems (PCSs), game apparatuses, security cameras, medical micro cameras, and robots.
The CMOS image sensor may include a photodiode sensing external light and a circuit generating data by converting the light into an electrical signal. When the amount of light received by the photodiode increases, the photo sensitivity of the CMOS image sensor improves.
The CMOS image sensor may have a pixel area and a circuit area on or in a semiconductor substrate. The pixel area may include a plurality of photodiodes, a plurality of color filters formed corresponding to the respective photodiodes to transmit light of a desired (or alternatively predetermined) wavelength range, and a plurality of lenses formed corresponding to the respective color filters. The circuit area may include at least one driver circuit driving the CMOS image sensor.
Conventionally, CMOS image sensors may be manufactured in a backside illumination sensor (BIS) structure. However, when CMOS image sensors are made in the BIS structure, heat or noise generated at the driver circuit in the circuit area may be transferred to the pixel area through the semiconductor substrate. As a result, the temperature and the dark current of the photodiodes in the pixel area increase, which may cause inferiority such as dark shading in the image sensor. Moreover, the noise transferred from the circuit area to the pixel area may deteriorate the quality of picture in the image sensor.